Hello Devishree Brahmbhatt,
Thank you for the response. This problem is getting very critical for our project.
We have a reference field on a form (on our module). This field is supposed to be filled by an onchange event from another field on the same form. After the onchange function is called, it successfully fill other fields but this reference field. This reference field will be filled if I test this with a GTK client. That means, I have the issue with Webclient only.

To recreate the issue, you will need one reference field on the form, and onchnage on another field. fill the reference field with value form onchange. the reference field will be filled if you are testing from GTK and will not be filled if you are testing form